Gene flow, colonisation and demographic history of the flat oyster Ostrea angasi

2005 ◽  
Vol 56 (8) ◽  
pp. 1099 ◽  
Author(s):  
David A. Hurwood ◽  
Mike P. Heasman ◽  
Peter B. Mather

The Australian flat oyster Ostrea angasi is currently being assessed for its potential as a species for culture in New South Wales. It is considered important to determine the population genetic structure of wild stocks among estuaries before translocation of juveniles (spat) for growout in order to avoid possible deleterious effects of hybridisation of genetically divergent stocks (i.e. outbreeding depression). Five estuaries were sampled in southern New South Wales as well as another four from across the natural range of the species in Australia. Sequence analysis of a 594 base pair fragment of the mitochondrial cytochrome oxidase I gene was used to determine the degree of population structuring inferred from pairwise ΦST estimates and spatial analysis of molecular variance analysis. The analyses revealed that there is no significant genetic differentiation among the sampled New South Wales estuaries (P > 0.05) and all eastern samples represent a geographically homogeneous population. This essentially removes any potential constraints on broodstock sourcing and spat translocation within this region. Although levels of differentiation among all sites varied, little divergence was evident across the entire range of the sample. Furthermore, the study revealed extremely low levels of divergence between O. angasi and its northern hemisphere congener, O. edulis, raising the possibility that O. angasi may have only recently colonised Australian estuaries.

2008 ◽  
Vol 1 (1) ◽  
Author(s):  
Jurgen Tampke

From the beginning German-speaking people have played a small but significant part in the history of Sydney. In fact the colony’s first governor, Arthur Phillip, was of German–English parentage: his father, a German teacher in London, came from the Hessian town of Frankfurt. Phillip Schaeffer, the Supervisor of the First Fleet, was also of Hessian background, and so was Augustus Alt, the first Surveyor of Lands in New South Wales. Alt played an important part in the design and construction of Sydney during the first ten years. On retirement both men joined the ranks of the colony’s early free settlers.


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